Control valves are commonly used in process control systems to control the flow of process fluids. A control valve typically includes an actuator (e.g., a pneumatic actuator, a hydraulic actuator, etc.) operatively coupled to a flow control member of a fluid valve to automate the control valve. In operation, a controller (e.g., a positioner) is often employed to supply a control fluid (e.g., air) to the actuator which, in turn, positions the flow control member (e.g., a valve gate, a plug, a closure member, etc.) to a desired position relative to a valve seat to control or regulate the fluid flow through the valve.
In some examples, a yoke may be employed to couple the actuator to the fluid valve. Additionally, in some instances, the controller may be mounted to the yoke. In some examples, external tubing may be employed to fluidly couple a control fluid between the controller and a chamber (e.g., a pressure chamber) of the actuator. However, the external tubing may become damaged or dislodged, thereby affecting the accuracy of the actuator and, thus, a desired fluid flow through the valve. In other examples, an internal pathway may be defined within the yoke to fluidly couple a control fluid between a controller and a lower pressure chamber of an actuator. However, in these examples, external tubing is required to fluidly couple the control fluid between the controller and an upper pressure chamber of the actuator.